1. Field of the Invention
The present invention relates to a wood fiberboard comprising wood fibers bound together with a binder resin. More specifically, the present invention relates to a wood fiberboard in which dimensional variation due to moisture is low, and from which the amount of formaldehyde discharge is low.
This application is based on patent application No. Hei 11-87248 filed in Japan, the content of which is incorporated herein by reference.
2. Description of the Related Art
Wood fiberboards, such as medium density fiberboard (hereinbelow referred to as MDF) comprising wood fibers bound together with binder resin, are superior in strength, have low anisotropy, and they are easily processed due to their homogeneity. These wood fiberboards can be used to obtain formed products which are not only flat in shape but which are also of curved shape, and they are widely used as materials, such as for furniture, and building materials.
In melamine type MDF, in which the wood fibers are bonded together by means of melamine resin, and MDI type MDF, in which the wood fibers are bonded together by means of MDI, the dimensional variations due to hygroscopicity and water absorption are great.
In addition, for 100% acetylated board in which the wood fibers (100% of which have been subjected to an acetylation treatment) are bonded together using MDI, the dimensional variation due to moisture is extremely small, and the formaldehyde discharge is in agreement with E0, however, the acetylation treatment is expensive and the final cost of the wood fiberboard is high.
Therefore, an object of the present invention is the provision at low cost of a wood fiberboard for which the dimensional variation due to moisture is small, and the formaldehyde discharge is low.
The wood fiberboard of the present invention is a wood fiberboard in which wood fibers which have been subjected to an acetylation treatment and wood fibers which have not been subjected to an acetylation treatment are bonded together using a binder resin, and wherein the content of the wood fibers which have been subjected to an acetylation treatment is 35 to 90% by weight of the total amount of wood fibers which have been subjected to an acetylation treatment and wood fibers which have not been subjected to an acetylation treatment.
The manufacturing method of the present invention comprises conducting heat and pressure forming a mixture containing wood fibers which have been subjected to an acetylation treatment, wood fibers which have not been subjected to an acetylation treatment, and a binder resin, wherein the amount of wood fibers which have been subjected to an acetylation treatment is 35 to 90% by weight of the total amount of wood fibers which have been subjected to an acetylation treatment and the wood fibers which have not been subjected to an acetylation treatment.
The wood fiberboard of the present invention is superior in its balance of properties such as having good dimensional stability, the ability to sufficiently maintain strength such as modulus of rupture, a low amount of formaldehyde discharge, and in addition it is possible to keep costs low.